Hydraulic systems having independent control of fluid into and out of an actuator is generally known, such as that illustrated in FIGS. 6 and 12 of U.S. Pat. No. 4,662,601 which issued May 5, 1987. In these known systems, a separate poppet or check type of valve has been used to control the flow into and out of each end of the actuator. The above noted patent also provides a float mode of operation. Various types of poppet valves and various control schemes have been set forth to control the opening and closing of the valving element within the poppet valve. One such poppet valve and control scheme is set forth in U.S. Pat. No. 5,421,545 which issued Jun. 6, 1995 and is assigned to Caterpillar Inc. The poppet valve of '545 is effective to proportionally control the flow therethrough. However, when used in a fluid circuit that desires to provide selective flow regeneration from the one end of an actuator to the other end of the actuator or a float function, the control scheme becomes complicated. It is known to provide flow regeneration in fluid circuits using a poppet valve arrangement between a multiple position control valve and the actuator. However, when using a multi-position control valve, the ability to independently control the flow into and out of the respective ends of the actuator is limited. It is desirable to provide a fluid circuit that has the ability to independently control the fluid flow into and out of an actuator while also providing the ability to regenerate flow from the one end to the other end.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.